How to Apply Lime to Your Lawn

Only apply lime if a soil test shows pH below 6.0. Do not lime based on a neighbor's recommendation, a lawn calendar, or a guess. Over-liming raises pH above 7.5 which locks out iron and manganese, causing yellow chlorotic grass that's worse than the original problem. A soil test costs $15 to $30 and tells you exactly how much lime you need.

Pelletized (granular) lime is the easiest for homeowners. It spreads evenly through a broadcast spreader and doesn't create dust clouds. Agricultural lime (powdered) is cheaper per ton but messy to apply and drifts in wind. Dolomitic lime adds magnesium if your soil test shows a deficiency. Calcitic lime is standard if magnesium is adequate.

Your soil test report specifies the exact amount. General guidelines: to raise pH by 0.5 points in clay soil, apply 40 to 50 lbs per 1,000 sq ft. In sandy soil, 25 to 30 lbs per 1,000 sq ft for the same change. Sandy soils need less lime because they have lower buffering capacity. Never exceed 50 lbs per 1,000 sq ft in a single application.

Use a rotary broadcast spreader set to the bag's recommended setting. Apply in two perpendicular passes at half rate for even coverage. Cover the entire lawn including edges. After spreading, water lightly (quarter inch) to wash pellets off grass blades and begin dissolving into the soil. The lime needs soil contact to react.

Lime takes 3 to 6 months to fully change pH. Do not reapply sooner. Test again in 6 months. If pH hasn't reached the target, apply a second round at a reduced rate. In very acidic soils (pH below 5.5), full correction may take 2 to 3 annual applications. Each fall application moves pH closer to the target.